Numerous efforts have been made to replace a defective human heart with a mechanical device which replicates the pumping action of a normal human heart. Canadian published patent applications 2,105,908 and 2,105,935 to Mussivand et al, filed Sep. 10, 1993 both relate to hydraulically actuated mechanical pumps for duplicating blood pumping action of the human heart. A right ventricular assist device is shown in Canadian patent 1,234,953 which utilizes an elliptical chamber with a flexible diaphragm separating a sac for connection to the patient's blood system and a pressurizing chamber for augmenting the flow of blood from the sac.
U.S. Pat. No. 3,734,648 relates to a mechanical heart which injects a driving fluid into one side of a diaphragm dividing a chamber to cause the evacuation of blood from the opposite side of the chamber. The system includes a piston pump and an accumulator for the driving fluid. U.S. Pat. No. 5,578,077 of Nov. 26, 1996 teaches the use of a scroll type pump modified for medical applications. U.S. Pat. No. 5,549,667 teaches an external mechanical heart having blood contacting parts made of Zirconium and alloys thereof. U.S. Pat. No. 4,547,911 of Oct. 22, 1995 relates to an implantable heart pump which runs at a harmonic multiple of a normal heart beat frequency, thereby reducing the pump chamber volume.
Thus many inventors have attempted to duplicate the pumping action of the human heart in an implantable mechanical heart.